Like naughty boys from an after-school detention, the Pisa rankings are finally out and, yet again, we in the UK are not marching confidently in the company of the global big boys. In fact, it appears that we have fallen further behind.

In my case it's especially humiliating. I spent a couple of hours over the weekend with a TOTALLY TOP SECRET advance copy of the international league tables and, several hours on, and despite trying to sharpen my concentration with wine sourced from various middle-ranking jurisdictions, I still couldn't make head nor tail of them.

I'm not sure what the Finnish word for 'dunce' is or the Cantonese for 'blob' but I accept that my quizzical response to the Pisa party will brand me an enemy of promise.

So, with depressing predictability, we are reminded of the defining feature of our education system: politicians can't leave it alone.

I remember listening to David Laws speaking before the last election. He promised that education would have an independent commission and that any new curriculum would be subject to a 10-year moratorium. Never such innocence again.

As a headteacher of 11 years, never has it been so difficult for me to concentrate on what brought me into the profession and what matters most: the quality of teaching.

That tells you a lot. I am unconvinced that the plethora of reforms will help us to develop more great teachers, and nor will the constant sniping at the profession do much to motivate us to keep improving.

This isn't complacency, by the way. Of course we need to do better. But let's compare like with like. I know from our links with schools in Shanghai and Finland that culture matters. The deep and driven culture of parental aspiration that we see, for example, in the Chinese schools we visit is extraordinary. There's an almost palpable sense of every young person wanting to achieve more than their parents.

I also know that teachers from Shanghai frequently come to visit us. They admire our innovation. They praise the quality of our A-levels. They crave our students' creativity and our emphasis on extra-curricular learning. They appreciate that we see great schools as about building character.

So I'm not going to beat myself into a pulp of psychological unhappiness because we aren't top of the Pisa pops. Instead I just hope that these results might serve as a marker.

It's now time to stop the media-pleasing gimmicks of educational policy, the tinkering with structures, and instead to focus on the only two things that matter: higher aspirations in the earliest years of a child's life and doing everything to develop ever-better teachers – people who are proud to be part of a great profession on a serious mission to improve the life-chances and attainment of our young people.

Andrew Sparrow's rolling coverage of all the day's political developments as they happen, including Boris Johnson hosting his LBC phone-in, the publication of the international Pisa school ranking tables, and Michael Gove's statement on them